Live video productions such as TV productions are realized today using vision mixers. Vision mixers are commercially available e.g. from the companies Grass Valley, Sony, Snell, and Ross.
A vision mixer is a device used to select between different video input signals to generate a video output signal. Besides creating different kinds of transitions the vision mixer can generate a multitude of video effects and comprises keyers, matte generators, text generators etc. By means of the vision mixer the user also controls the routing of signals from various sources to selectable destinations.
The vision mixer also performs the routing and switching of audio signals accompanying the video signals. However, since the processing of video signals is more complex than the processing of audio signals the present patent application is focused on the video signal. It is to be understood that in the context of the present patent application the processing of the video signal also implies a corresponding processing of an accompanying audio signal. Only for the sake of better intelligibility of the description of embodiments of the present invention audio signals are not always mentioned in addition to the video signals.
In order to enable a multitude of functionalities, vision mixers consist of a huge amount of hardware components to process the video signals. The processing hardware components are located in one housing and are connected with local bus solutions in order to control all video processing hardware in real-time to meet the fast control requirements of live productions.
A conventional vision mixer comprises a central mixing electronic, several input channels and at least one output channel, a control unit and a user interface. Such kind of vision mixer is described for example in DE 103 36 214 A1.
Live video productions like news, sports and stage events are produced in fixed or mobile TV studios. Conventionally, a TV studio is equipped with a vision mixer, multi-viewer and monitor walls, storage systems and digital video effects devices, external crossbars and the like. All these devices consist of a big amount of dedicated hardware stages, external cabling and specific configurations settings reflecting the internal and external hardware structure and connectivity. The entire TV live production is controlled by operating a control unit controlling the devices. For historical and architectural reasons the operation and configurations of the control interface for these devices is hardware oriented. For this reason the operator of the TV live production has to keep simultaneously in mind two completely different views on a TV production, namely the sequence of the scenes of the TV production on the one hand and the hardware operations required for obtaining the desired workflow of the scenes. These two different views on the same live TV production have nothing to do with each other. Therefore, the task of operating a live TV production is complicated. But it is made even more complicated due to the fact that the operator can influence almost all hardware components. Consequently, there is a significant risk to execute mal-functions such as losing an input signal which is required for a scene which is currently on-air. At the same time, the operator cannot access all functionalities needed for the workflow of the scenes without setting certain delegation levels.
Existing operating interfaces for conventional TV live production systems are inflexible because they are tied to the underlying hardware of the devices used for a TV production. This makes them also very complicated and their operation is frequently counter intuitive. As such TV live productions are error prone unless special efforts are made to support the operator.